1. Field of the Invention
The present invention relates to a water-sealing sheet used in the various civil engineering and construction works.
2. Description of the Prior Art
In the various civil engineering and construction works, water-sealing sheets for preventing water leakage have been conventionally used
1 between the segment of sealed tunnel and the second covering,
2 between water-sealing boards such as steel sheet pile and concrete,
3 between underground continuous wall and concrete, and
4 between the junction portion of box culvert and its outer peripheral portion.
Examples used as the above-mentioned water-sealing sheet include polyvinyl chloride sheets such as plasticized PVC sheet and ultra plasticized PVC sheet which are excellent in the elasticity and have the ductility to follow the crustal movement. However, in spite of the fact that these polyvinyl chloride sheets have the tensile strength of 140 kgf/cm.sup.2 or more, they are easy to suffer from tears or pinholes by scratching during the processing work and water leakage cannot be prevented reliably.
On the other hand, water-sealing sheets comprising water-swelling urethane resin have been also used in the various civil engineering and construction works. However, although these sheets have durability, there are such problems as that they have not the sufficient elasticity, so that the following the crustal movement is insufficient.